P111 Proactive therapeutic drug monitoring is not associated with lower rates of steroid exposure or excess in adalimumab treated IBD patients

Introduction Therapeutic drug monitoring (TDM) may be used as a treatment monitoring tool in individuals with inflammatory bowel disease (IBD) treated with anti-TNF biologics. TDM measures serum drug levels (DL) and guides clinicians to optimise drug efficacy through the adaptation of frequency of administration or dose. In general, TDM is utilised in strategies described as proactive (pTDM) or reactive (rTDM). In rTDM, DLs are measured in response to a change in clinical symptoms. In pTDM, DLs are measured routinely to allow dose optimisation prior to clinical symptoms developing. Although evidence supports the use of TDM in clinical practice, there is a paucity of data demonstrating benefit relating to clinically important outcomes.1–3 Minimising steroid exposure is an important clinical goal for individuals with IBD, as excessive steroid use continues to pervade in UK practice.4 The aim of this study was to assess the impact of pTDM and rTDM on steroid exposure in our local IBD population treated with adalimumab. Methods Patient data was identified using the West of Scotland NHS Safe haven. Patients with IBD, treated with Adalimumab, undergoing TDM, were included. Patients were allocated to proactive (pTDM) or reactive (rTDM) groups. Steroid (prednisolone) prescribing and drug levels were reviewed from January 2018-December 2019. Annual steroid excess was defined as 2 or more steroid prescriptions in 12 months.1 SPSS was used to perform Chi-squared and Mann-Whitney U tests Results 390 patients were included; 328 in the pTDM group and 62 in the rTDM group. 465 TDM tests were performed in total; 395 proactively and 70 reactively. There was no difference (p=0.903) in DLs between pTDM and rTDM groups. 172/390 (44.1%) patients were exposed to steroids in the 2 year study period, 122/390 (31.8%) in excess. Comparing pTDM and rTDM groups, no difference was seen for steroid exposure vs none (p=0.063), or steroid excess vs none (p=0.094). Conclusions Steroids are commonly prescribed in our IBD population. The TDM testing strategy used did not impact on steroid prescribing in patients treated with adalimumab. Further work is required to explore this observation and determine whether DLs are a factor in influencing clinical decision making around steroid use. Furthermore, the relationship between TDM and other important clinical outcomes such as hospital admissions and IBD related surgeries should be examined. References Lamb CA, et al. Gut 2019;68:s1-s106. Raine T, et al. JCC 2022;16(1):2–17. Torres J, et al. JCC 2020;14(1): 4–22. Rosiou K, et al. Aliment Pharmacol Ther 2022;56:501–509.